Question about PC DM

Well, I have a Mac and have used it recently to do my backups and to sync my iTunes music and iPhoto pics.

BUT, when I sync with my Mac, I can't get Japanese text with the Mac AppLoader and it also deletes all of my alerts...

So, I have my BB set to be able to sync with two computers, but if I go on my friend's PC and download BB DM and then use it to App Load Japanese text and my alerts back on will anything mess up with my OS, etc? Just want to make sure I don't loose any of my apps and the such.